Work on #403, added class diagrams and javadocs

promise/src/main/java/com/iluwatar/promise/App.java

@@ -1,5 +1,28 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.promise;
 
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ExecutorService;
@@ -7,14 +30,31 @@ import java.util.concurrent.Executors;
 
 /**
  * 
- * Application that uses promise pattern.
+ * <p>The Promise object is used for asynchronous computations. A Promise represents an operation that
+ * hasn't completed yet, but is expected in the future.
+ * 
+ * <p>A Promise represents a proxy for a value not necessarily known when the promise is created. It 
+ * allows you to associate dependent promises to an asynchronous action's eventual success value or 
+ * failure reason. This lets asynchronous methods return values like synchronous methods: instead of the final
+ * value, the asynchronous method returns a promise of having a value at some point in the future.
+ * 
+ * <p>Promises provide a few advantages over callback objects:
+ * <ul>
+ * <li> Functional composition and error handling
+ * <li> Prevents callback hell and provides callback aggregation
+ * </ul>
+ * 
+ * @see CompletableFuture
  */
 public class App {
 
+  private App() {
+  }
+  
   /**
    * Program entry point
    * @param args arguments
-   * @throws InterruptedException if main thread is interruped.
+   * @throws InterruptedException if main thread is interrupted.
    * @throws ExecutionException if an execution error occurs.
    */
   public static void main(String[] args) throws InterruptedException, ExecutionException {

promise/src/main/java/com/iluwatar/promise/Promise.java

@@ -1,3 +1,25 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.promise;
 
 import java.util.concurrent.Callable;
@@ -8,6 +30,7 @@ import java.util.function.Function;
 
 /**
  * Implements the promise pattern.
+ * 
  * @param <T> type of result.
  */
 public class Promise<T> extends PromiseSupport<T> {
@@ -41,7 +64,7 @@ public class Promise<T> extends PromiseSupport<T> {
     postFulfillment();
   }
 
-  void postFulfillment() {
+  private void postFulfillment() {
     if (fulfillmentAction == null) {
       return;
     }

promise/src/main/java/com/iluwatar/promise/PromiseSupport.java

@@ -0,0 +1,119 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.promise;
+
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+/**
+ * A really simplified implementation of future that allows completing it successfully with a value 
+ * or exceptionally with an exception.
+ */
+class PromiseSupport<T> implements Future<T> {
+
+  static final int RUNNING = 1;
+  static final int FAILED = 2;
+  static final int COMPLETED = 3;
+
+  final Object lock;
+
+  volatile int state = RUNNING;
+  T value;
+  Exception exception;
+
+  PromiseSupport() {
+    this.lock = new Object();
+  }
+
+  void fulfill(T value) {
+    this.value = value;
+    this.state = COMPLETED;
+    synchronized (lock) {
+      lock.notifyAll();
+    }
+  }
+
+  void fulfillExceptionally(Exception exception) {
+    this.exception = exception;
+    this.state = FAILED;
+    synchronized (lock) {
+      lock.notifyAll();
+    }
+  }
+
+  @Override
+  public boolean cancel(boolean mayInterruptIfRunning) {
+    return false;
+  }
+
+  @Override
+  public boolean isCancelled() {
+    return false;
+  }
+
+  @Override
+  public boolean isDone() {
+    return state > RUNNING;
+  }
+
+  @Override
+  public T get() throws InterruptedException, ExecutionException {
+    if (state == COMPLETED) {
+      return value;
+    } else if (state == FAILED) {
+      throw new ExecutionException(exception);
+    } else {
+      synchronized (lock) {
+        lock.wait();
+        if (state == COMPLETED) {
+          return value;
+        } else {
+          throw new ExecutionException(exception);
+        }
+      }
+    }
+  }
+
+  @Override
+  public T get(long timeout, TimeUnit unit)
+      throws InterruptedException, ExecutionException, TimeoutException {
+    if (state == COMPLETED) {
+      return value;
+    } else if (state == FAILED) {
+      throw new ExecutionException(exception);
+    } else {
+      synchronized (lock) {
+        lock.wait(unit.toMillis(timeout));
+        if (state == COMPLETED) {
+          return value;
+        } else if (state == FAILED) {
+          throw new ExecutionException(exception);
+        } else {
+          throw new TimeoutException();
+        }
+      }
+    }
+  }
+}

promise/src/test/java/com/iluwatar/promise/AppTest.java

@@ -1,3 +1,25 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.promise;
 
 import java.util.concurrent.ExecutionException;

promise/src/test/java/com/iluwatar/promise/PromiseTest.java

@@ -1,3 +1,25 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.promise;
 
 import static org.junit.Assert.assertEquals;